import java.util.ArrayList;

import org.junit.Test;

/**
 * leetCode 26：Remove Duplicates from Sorted Array
 * 给定升序数组array，删除重复元素，并返回新的长度len；使得前len个数字升序，并且不得含有重复数字；后面的数字是什么，无所谓。
 */
public class _026RemoveDuplicates {
    /**
     * 借助ArrayList解决问题
     */
    public int remove01(int[] nums) {
        if (nums == null || nums.length == 0) {
            return 0;
        } else if (nums.length == 1) {
            return 1;
        } else {
            int end = nums.length - 1;
            ArrayList<Integer> list = new ArrayList<Integer>();
            int i = 0;
            while (i <= end) {
                if (i == end) {
                    list.add(nums[i]);
                    i++;
                } else {
                    int j = i + 1;
                    if (nums[i] == nums[j]) {
                        while (j <= end && nums[i] == nums[j]) {
                            j++;
                        }
                    }
                    list.add(nums[i]);
                    i = j;
                }
            }
            for (i = 0; i < list.size(); i++) {
                nums[i] = list.get(i);
            }
            return list.size();
        }
    }

    /**
     * 模拟System.arraycopy()
     * 
     * @param array1 源数组
     * @param s1 源数组的开始位置
     * @param array2 目标数组
     * @param s2 目标数组的开始位置
     * @param len 需要复制的元素的个数
     */
    public void myArrayCopy(int[] array1, int s1, int[] array2, int s2, int len) {
        int[] array = new int[len];
        for (int i = 0; i < len; i++) {
            array[i] = array1[s1 + i];
        }
        for (int i = 0; i < len; i++) {
            array2[s2 + i] = array[i];
        }
    }

    /**
     * 借助ArrayCopy解决问题
     */
    public int remove02(int[] nums) {
        if (nums == null || nums.length == 0) {
            return 0;
        } else if (nums.length == 1) {
            return 1;
        } else {
            int end = nums.length - 1;
            for (int i = 0; i <= end; i++) {
                if (i < end) {
                    int j = i + 1;
                    if (nums[i] == nums[j]) {
                        while (j <= end && nums[i] == nums[j]) {
                            j++;
                        }
                    }
                    System.arraycopy(nums, j, nums, i + 1, end - j + 1);
                    // 用myArrayCopy 有时候Accepted，有时候 Time limit exceeded
                    // 同学们可以多提交几次，估计是判题系统的问题
                    // myArrayCopy(nums, j, nums, i+1, end-j+1);
                    end -= j - i - 1;
                }
            }
            return end + 1;
        }
    }

    /**
     * 借助临时变量解决问题
     */
    public int remove03(int[] nums) {
        if (nums == null || nums.length == 0) {
            return 0;
        } else if (nums.length == 1) {
            return 1;
        } else {
            int temp = nums[0];
            int len = 1;
            for (int i = 1; i < nums.length; i++) {
                if (temp == nums[i]) {
                    continue;
                } else {
                    temp = nums[i];
                    nums[len] = nums[i];
                    len++;
                }
            }
            return len;
        }
    }

    public void printNewArray(int[] array, int len) {
        for (int i = 0; i < len; i++) {
            System.out.print(array[i] + " ");
        }
        System.out.println();
    }

    @Test
    public void test01() {
        int[] nums = {1, 2, 2, 2, 3, 4, 5, 6, 6, 7, 7, 7, 8};
        int len = remove01(nums);
        System.out.println(len);
        printNewArray(nums, len);
    }

    @Test
    public void test02() {
        int[] nums = {1, 2, 2, 2, 3, 4, 5, 6, 6, 7, 7, 7, 8};
        int len = remove02(nums);
        System.out.println(len);
        printNewArray(nums, len);
    }

    @Test
    public void test03() {
        int[] nums = {1, 2, 2, 2, 3, 4, 5, 6, 6, 7, 7, 7, 8};
        int len = remove03(nums);
        System.out.println(len);
        printNewArray(nums, len);
    }
}
